The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
In a typical wireless network, when distance between two devices such as mobile phones is more than transmission/reception range, intermediate nodes are required to provide communication services between the devices. Such intermediate nodes are generally referred to as relay nodes that are used to send information between two devices. Relevance of a relay node and relay architecture in today's radio access networks such as 4G long term evolution (LTE) and next generation radio access network (5G) has increased as network operators try to achieve enhanced coverage and capacity.
Different technologies such as multiple input multiple output (MIMO), orthogonal frequency-division multiplexing (OFDM) and other advanced error correction techniques are being used by wireless networks to improve throughput under many conditions, however these technologies do not fully mitigate the problems experienced at a cell edge. As cell edge performance is becoming more critical, it is necessary to enhance performance of the cell edge at comparatively low cost. Cell edge performance depends on relay node performance.
A typical LTE network includes a plurality of base transceiver stations (BTS), also referred to as eNodeBs, a plurality of user equipments (UE) that connect to one or more eNodeBs for accessing voice or data service, a plurality of relay nodes (RN), also referred to as relays, and a plurality of repeaters. Network elements of system architecture evolution (SAE) include mobility management entity (MME), serving gateway (SGW), and packet data network Gateway (PDN-GW). In LTE network, eNodeB is generally responsible for complete radio resource management and allows a UE to access any network service. Multiple eNodeBs connect to evolved packet core (EPC) using MME for control plane signaling and also connect to SGW for user plane data transfer. SGW in a network is generally connected to a packet data network gateway (PDN-GW or PGW) for providing connectivity to external networks, including the public Internet. There are various types of eNodeBs available such as Macro/Wide-area, Micro/local-area, Pico/Small-area, Femto/home, which can respectively be called as Macro BTS, Micro BTS, PiCo BTS and Femto BTS.
In a network, repeaters or relay nodes are used generally to extend coverage of an existing BTS. They re-transmit uplink and downlink signals without decoding any of the content. First antenna of a repeater can be directed towards donor cell while second antenna can be directed towards target coverage area. As the target coverage area could be an indoor location, it may be required that one of the antenna to be an indoor antenna. Some functionalities of repeaters and relay nodes are same, however some of the functionalities are different. For example, a relay node can have its own cells and protocol stack, and also relies upon a radio frequency (RF) connection to a donor cell. The relay is similar to a normal BTS but without a fixed or wired transport connection, and can decode signals to make radio resource management decisions. PGW connects to a packet data network, which could be an external network (either public or private) or belong to the operator. The network architecture may also contain other network elements such as home subscriber server (HSS), equipment identity register (EIR), and policy and charging rules function (PCRF) etc. and different interfaces connecting all the network elements, according to 3GPP specifications.
There are different relay architectures, relay nodes, and methods thereof for relay management that are known in the prior art. FIG. 1 illustrates an existing relay architecture variant. One type of classification is the relay architecture where the relays are classified as architecture A and other type of classification is where the relays are classified as architecture B. Each of these architecture, as shown in FIG. 1, have different variants such as architecture A has three below known variants:
Alt 1: Full-L3 relay
Alt 2: Proxy S1/X2-Home eNodeB GW function at eNodeB
Alt 3: RN bearer terminates in DeNodeB.
Similarly architecture B has different variants, for example Alt 4: S1 UP terminated in donor eNodeB (DeNB). Further, relay nodes may also be classified depending on layers such as layer 1, layer 2, and layer 3 relay nodes.
In another classification, relay nodes can be classified as Type 1 and Type 2 relay nodes, wherein Type 1 LTE relay nodes control their cells with their own identity including the transmission of their own synchronization channels and reference symbols. Type 1 relays appear as if they are a Release 8 eNB to Release 8 UEs and ensures backward compatibility. The basic Type 1 LTE relay provides half duplex with in-band transmissions. Type 1 LTE can further be classified as Type 1.aLTE relay nodes (RNs) that are outband RNs that have same properties as the basic Type 1 relay nodes but can transmit and receive at the same time i.e. full duplex. Type 1.bLTE relay nodes are inbandRNs that have an ample or adequate isolation between antennas used for BS-RN and RN-UE (UE attached to RN), which isolation can be achieved by adjusting antenna spacing, directivity along with specialized digital signal processing techniques, which in turn impacts cost. Performance of these RNs and fem to cells can be similar.
Type 2 LTE relay nodes do not have their own cell identity and look just like main cell. Any UE in range cannot make distinction between a relay node from the main eNB within the cell. Control information can be transmitted from the eNB and user data from the LTE relay.
LTE Relay ClassCell IDDuplex FormatType 1YesInbandhalf duplexType 1.aYesOutband full duplexType 1.bYesInband full duplexType 2NoInband full duplex
One of the known problems with these relay nodes is that these relay nodes are not transparent to eNodeB and add extra cost. Another problem with existing relay nodes is that the eNodeB must support RN protocol stack for transfer of user plane data and perform signaling. Yet another problem with existing relay nodes is of modified air-interface, called as “Un” interface to user and control plane. The existing relay network poses some of the problems as highlighted in the 3GPP specification such as radio resource configuration between RN and eNB which adds extra cost, RN subframe configuration information element adds extra cost and also a new relay specific scheduler is required. The existing relay node of any architecture and type specified in 3GPP requires enhancements to eNodeB (eNB) and evolved packet core (EPC) elements.
There is therefore a need in the art for a system and method for building a new relay node that does not require any change to eNodeB, protocol stack, UE and EPC elements, and is different from what other standard development organizations (SDOs) are proposing and can work efficiently without impacting existing radio access network (RAN) or core network (CN) deployment. Further, another need is to eliminate support needed from incumbent vendors. Also, there is a need for a low cost relay node with simple architecture that provides mobility support, out of band configuration, full duplex capability, reusable cell ID, reusable spectrum configuration.
All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
In some embodiments, the numbers expressing quantities or dimensions of items, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability.